The 46-year-old actor took to Facebook on Tuesday to express his reservations about finishing Fast & Furious 7 without the late star. Walker had finished most of his scenes before his death in November 2013, but his brothers Caleb and Cody were brought on to "fill in small gaps in production."

"With our new ambitious vfx team, the whole cast and crew has had to adjust to this awkward and uncomfortable process of pixels over people," Vin Diesel writes. "Aside from the obvious strains it places on the director, the challenge is not to allow it to compromise what makes the character so special."

The actor praised his friend and costar earlier in the post, saying, "There wasn't a scene in the saga he didn't want to discuss, improve... even with just a changing of a line or adding a specific nuance to enrich a moment."

"He did it with the pride of knowing, that over a decade of portraying Brian, through four directors, multiple writers and new producers he was able to maintain the inner core of the character he created," he lauds. "He always knew I would fight for him... whether it was to protect his deal or to protect his integrity."

Fast & Furious 7 halted production for many months after Walker's death, and is scheduled for an April 10, 2015 release. An eighth movie is already planned, and Cody Walker will receive a new, recurring role in future Fast & Furious films.